In the field of health care, and particularly human diagnostics, point-of-care (POC) testing generally refers to laboratory tests outside of a central laboratory. POC has improved patient care efficiency as it allows diagnostic testing to be performed wherever a patient may be, including in some instance by the patent themselves. POC not only provides the patients with convenience of self health monitoring, but also allows remote medical record keeping and diagnoses, for example, by uploading the POC test results to a health professional's site through the Internet.
Impedance-based glucose sensors/test trips together with their dedicated reader apparatuses, such as ONETOUCH® produced by LifeScan Inc., are useful for quantitative assessment of blood glucose levels. The reader apparatuses can provide clear and understandable readouts to users, but usually are expensive and are designed for specific tests.
The cellular device industry's adoption of miniaturized cameras has demonstrated an alternative platform for off-site detection and diagnosis of disease, using colorimetric analysis. Recent studies show that camera phones can be used as portals for acquisition and transmission of images for rapid clinical assessment and treatment recommendations by off-site trained physicians.
Test strips that can be used with a general-purpose mobile terminal, such as a cellular phones (referred to as “glucophones”), eliminate the need for dedicated reader devices. Instead, the cellular phones can be used as general-purpose reader apparatuses for a variety of data readout, analysis, display, and transmission. For example, Healthpia USA has developed a glucose meter (“glucopack”), which replaces the battery cover of a cellular phone. Test strips are inserted into the glucopack to analyze glucose level results.
An existing diagnostic system uses test strips that exhibit color changes when brought in contact with a test sample, such as blood. The color changes of the test strips are read by a dedicated apparatus, or a general-purpose reader apparatus such as a mobile phone. The mobile phone may have the functionality of obtaining the color information of the test strips. The process may involve taking an image of the test strips using a camera of the mobile phone, and then transmitting the image to an external analysis system for data analysis and display to users. The test strips can be illuminated by the ambient light, or with an external light source.
FIG. 1 depicts a schematic diagram of another example of an existing diagnostic system that uses test strips 10 with an application-specific dedicated reader apparatus 20. When a test strip 10 is inserted into the reader apparatus 20, a light source 22 of the reader apparatus sends a light beam 24 to illuminate the detection region of the assay 26 of test strip 10. The assay 26 can include the test sample, a mixture of the sample and a reagent, or a reaction derivative from the sample. The reaction between the sample and the reagent, or a chemical reaction within the sample itself, can be stimulated using an electronic circuit 28. The transmitted light carries the information of the assay 26, such as color or opacity information, and is received by a photodetector 30 and analyzed by the reader apparatus 20.
Although glucophones can aid in diabetes management, they exhibit certain limitations, including added cost of the glucopack compartments, limited compatibility of the glucopack compartments with cellular phone models, and a lack of wireless and signal processing functionality on the paper strips.
Quantitative information relating to a sample also can be used for diagnoses of, for example, HIV, Malaria, etc. When a sample such as blood is placed onto a test strip, a pre-deposited assay changes color and informs the user whether a patient tests positive for an affliction (such as HIV or Malaria).
These existing devices may be prohibitively expensive for certain applications. For example, the reader apparatus might not be widely affordable in developing countries where mobile diagnostics are needed the most. In addition, in an environment such as a battle field, the users might not be able to afford the time to insert the test strip into the reader apparatus, or to carry the reader apparatus around.